Electric switch with improved disk and contact structure



I Jan. 31, 1957' D. W. JOHNSON ELECTRIC SWITCH WITH IMPROVED DISK ANDCONTACT STRUCTURE Filed June 30, 1965 F/GZ INVENTOR.

00 W0 M/ Johnson BY MS af/omeys ALMMMWK 2 Sheets-Sheet l ELECTRIC SWITCHWITH IMPROVED DISK AND CONTACT STRUCTURE Filed J1me 30, 1965 Jan. 31,1967 n. w. JOHNSON 2 Sheets-Sheet INVENTOR. Dav/c7 W Johnson BY h/saf/omeys United States Patent C) 3,301,971 ELECTRIC SWITCH WITH IMPROVEDDISK AND CONTACT STRUCTURE David W. Johnson, Newington, Conn., assignorto The Arrow-Hart & Higeman Electric Company, Hartford, Conn., acorporation of Connecticut Filed June 30, 1965, Ser. No. 468,366 16Claims. (Cl. 20011) This invention relates to electric switches and inparticular to a rotary, multi-position switch suitable for use with aprinted circuit.

Printed circuits are used in increasing numbers. Conventionally suchcircuits comprise conducting areas pr nted on one side of a flat panelor board. In many applications rotary switches capable of beingmanipulated to connect a primary terminal to any one of two or moresecondary terminals must be employed with or 1n such circuits. Oftenthese switches must be mounted on the panel, with terminal postsextending through the switch housing to be attached to or connected withthe conductive areas. As well as being capable of fitting snugly againstthe panel, such switches must be easy to manipulate, light in weight andin many cases of a construction highly resistant to vibration.

It is an object of the present invention to provide a rotary switchsuitable for use with printed circuits.

It is another object of the invention to provide a rotary switch capableof being securely attached to a flat panel and conveniently connected ina printed circuit on the panel.

It is another object of the invention to provide a rotary switch whichwill be light and easy to manipulate.

It is another object of the invention to provide a rotary switch whichis resistant to vibration.

Other objects will become apparent from a consideration of the followingspecification and claims.

In accordance with the invention the objects enumerated and others, areattained by means of a rotary switch comprising a base, a handlerotatable with respect to said base, a primary fixed contact, aplurality of secondary fixed contacts in said base, each of said fixedcontacts having a substantially disc shaped contacting element, amovable contact assembly, rotatable in said base and comprising anarcuate bifurcate section engaging the disc element of the primary fixedcontact and a bifurcate finger adapted to engage the disc shapedcontacting elements of the secondary fixed contacts, and meansconnecting said movable contact means with said handle whereby rotationof the handle causes rotation of the movable contact means.

The invention will be further described with reference to the drawingsin which:

FIG. 1 is a view, partly in side elevation and partly in verticalsection, of a switch made in accordance with the invention, showing thehandle and base of the switch.

FIG. 2 is a plan view of the switch of FIG. '1 with the handle removed.

FIG. 3 is a bottom plan view of the handle of the switch of FIG. 1showing the internal structure of the handle.

FIG. 4 is a plan view of the base of the switch of FIG. 1 with certainmovable elements removed.

FIG. 5 is a plan view of a movable contact as used in the switch of FIG.1.

FIG. 6 is an end view of the movable contact of FIG. 5.

FIG. 7 is a perspective view of a drive member for use in the switch ofFIG. 1.

Referring to the drawings, a switch 9 in accordance wit-h the inventioncomprises a base 10, which may be of cylindrical shape, and a handle 8.The base 10 has a bottom wall 11 and a circular side wall 12.Conveniently it may be molded from a synthetic resin.

bottom 11 are located a primary fixed contact 13 and Secured to the icethree secondary fixed contacts 14, 15 and 16. In FIG. 1, for clarity,the upper portion of the contact 14 has been omitted. These contacts arealike and the base 10 may be molded around them, as in the embodimentshown in the drawing, or they may be fixed in the base in any otherconvenient way. The primary fixed contact 13 is made in one piece andhas a terminal post 17 at its outer end, which post extends outside thebottom 11 of the base. Similarly terminal posts 18 and 19 form parts ofsecondary contacts 14 and 15, respectively. (The terminal post forsecondary contact 16 is not shown.)

The inner end of the contact 13 terminates in a substantially disc-likeor planar contacting portion 21 centrally supported by an axial portion22. The disc-like element 21 is preferably gently bevelled, on bothupper and lower surfaces for reasons to be described.

The secondary contacts 1416 are likewise provided with disc shapedcontacting elements 23, 24 and 25.

All of the fixed contacts are secured in position in the base 10 bymeans of inner disc-like flanges such as 26 and 27, and outer retainingprojections such as 28 and 29, shown in FIG. 1 for contacts 13 and 15.The inner flanges have their flat outer surfaces 30, 31 abutting theinner surface of the bottom 11 of the base 10 while their inner surfaces32, 33 are bevelled in a manner complementary to the surfaces of thecorresponding disc elements 21 and 24. The outer projections such as 28and 29 are luglike projections which may be forced down in a well suchas 34, provided in the outer surface of the base end wall 11.

As shown most clearly in FIG. 4, the internal structure a of the base 10comprises a central hub 35 having an aperture 36 and a ring 37concentric with the hub 35. The space between the ring 37 and the hub 35forms an annular channel 38. A strut 39 joins the ring 37 and the hub 35and blocks the channel 38 at a point which is opposite the primary fixedcontact 13.

'- images of one another.

1 side and a Referring again to FIGS. 1, 2, 5 and 6, a laminated movablecont-act assembly 40 is disposed in the switch abutting the hub 35. Thisassembly comprises two movable contact elements 41 and 42 which aremirror As shown in FIGS. 5 and 6 the element 41 is a highly conductivespring of thin sheet metal, such as a beryllium-copper alloy. It has anannular central part 43 with an aperture 44. An arcuate segment 45extends radially from the part 43 on one finger 46 extends radially fromthe opposite side. Two positioning tabs 47 and 48 extend radially fromopposite sides of the part 43 intermediate the arcuate section 45 andthe finger 46.

As shown in FIG. 6 the corners 72 and 73 of the finger are bent up.Similarly the corners 49 and 50 of the arcuate section 45 are bent up.

Corresponding corners on the other lamination of the movable contact 42are bent down. The complementary oppositely bent corners of the fingers46, 46a receive the bevelled surfaces of the disc-like elements 23, 24,

- receives fingers 46 and 46a of the movable contact assem 25 of thefixed contacts 14, 15 and 16. Similarly the bent up corners of thearcuate section 45, 45a receive the disc-like section 21 of the primaryfixed contact 13. I To position and move the movable contact assembly 40in the switch there is provided a drive, member 51. As will appear fromFIG. 7 the drive member 51 is a hollow cylindrical body made of a toughinsulating material such as nylon having a drive section 52 and apositioning section 53. The drive section 52 has exterior longitudinalfiuting 54. The positioning section is a sleeve having a cut out section55, and three longitudinal slots 56, 57 and 58. The positioning sectionis dimensioned to fit in the channel 38 of the base 10 with the strut 39in the cut out section 55. In this position the slot 56 bly 40 and theslots 57 and 58 receive positioning tabs a 47 and 48 of element 41 andshown) of element 42.

the corresponding tabs (not Two leaf springs 59 and 60, in the shape ofa lazy W are seated in slots 63, 64, 65 and 66 in the cylindrical wall12 of the base 10, so that the central vertices 61, 62 I of the Wsengage the fiuting of the drive member and which is shaped to receivethe fluted section 52 of the drive member 51. As shown in FIG. 1, thehandle is slipped over the drive member and retained in that position bya screw 68 which passes through the aperture 36 in the base, through thecentral apertures of the contact elements 41 and 42, through the centerof the drivemember 51 and is threaded into a tapped socket 69 in handle8. The handle 8 is provided with a shoulder 70 about its periphery, andthe screw 68 holds the handle 8,. against the action of a helical spring71 seated internally of the drive member 51, in a position such that theshoulder 70 of the handle engages the circular wall 12 of the base 10.

The operation of the device will be obvious. Turning the handle 8 turnsthe drive member 51 by virtue of the engagement of the fiutings in thatmember with the socket 67 in the handle. As the drive member turns itcams the leaf springs 59 and 60 so that the apexes of the Ws are forcedout of one fluting and into another.

The drive member also causes the bifurcate movable contact member 40 tobe turned. The fingers 46 and 46a of the individual elements 41 and 42thus slip from the disc element of one fixed contact to the next. At thesame time the arcuate members 45 and 45a slide across the disc element21 of the primary fixed contact 13 never breaking contact therewith.Thus a circuit may be established from the primary fixed contact 21through the movable contact assembly 40 to one of the secondary fixedcontacts.

It will be observed from the drawings that the dimensioning of the drivemember 51 and the location of the movable contacts 14, 15 and 16 aresuch that when the springs 59 and 60 are seated in a fluting of thedrive member, the finger of the movable contact engages one of thesecondary contacts. An indexing mark (not shown) may be applied to thetop of the handle 8, in line with one of the flutings in the socket 67.When the handle is assembled with such mark directly over the finger 46of the movable contact assembly, the index mark will indicate with whichfixed contact the movable contact assembly is engaged. The springs 59and "60* enter into the indexing or indicating operation by theircooperation with the fluting of the drive member 51 to insure stepwisemovement of said drive member and movable contact assembly, so that whenthe movable contact assembly is at rest it will always engage one of thefixed contacts 14, 15 or 16. In this connection it will be noted thatthe cut out section 55 on the positioning section of drive member 51permits the drive member only a limited angular movement which is keyedto the arcuate distance between contacts 14 and 16. Further movement isprevented by the sides of cut out section 55 coming up against the strut39 in the base Thus it will be seen that the present invention providesa simple multi-position rotary switch readily adaptable to mounting on aflat surface. Terminal posts 17, 18, 19 and 21? extending from the baseof the switch may be connected to printed circuits. The action of theswitch itself is positive. Becausecontact is made by a bifurcate movablecontact member having elements on both sides of the fixed contactmembers, and because the helical spring 71 maintains pressure on themovable contact vibration has a minimal effect. All parts except thecontacts and the springs may be molded from synthetic resins with theadvantages of light weight and low cost.

It will be obvious that various changes may be made in the structurespecifically shown and described herein without departing from the scopeof the invention. In particular it may be pointed out that any number ofsecondary fixed contacts may be used.

What is claimed is:

1. A rotary switch comprising:

a cylindrical base having a bottom and a side wall, said bottom having acentral hub, a ring about said hub, said ring and said hub defining anannular channel and a strut extending across said channel from said ringto said hub;

a primary fixed contact in said base and a plurality of secondary fixedcontacts in said base, each of said fixed contacts having a disc shapedcontacting element;

a movable contact assembly comprising a bifurcate arcuate section forengaging the disc shaped element of the primary fixed contact and abifurcate finger for engaging the disc-like members of the secondarycontacts;

a hollow cylindrical drive member having a fluted section and apositioning section, said positioning section fitting in the annularchannel of said base and having means engaging the movable contactassembly whereby rotation of said drive member causes rotation of thecontact assembly;

a leaf spring seated in said :base and engaging the fiuting of the drivemember to provide indexing when said drive member is rotated;

a handle having a socket engaging the fluted section of the drivemember, whereby turning said handle turns said drive member;

a helical spring in said hollow drive member pressing upon said movablecontact assembly; and

a bolt passing through the hub of said base and threaded in said handleto hold said handle to said base against the action of said helicalspring.

2.'The rotary switch claimed in claim 1, wherein the drive member has acut out section fitting over the strut extending across the annularchannel in the bottom of the switch, contact between the sides of saidcut out section and the strut limiting rotational movement of the drivemember. I

3. The rotary switch claimed in claim 1 wherein said movable contactassembly comprises two contact elements, placed face to face, eachhaving an arcuate section at one end and .a finger at the other, thecorners ofthe arcuate sections and of the fingers being bent to formentrances.

4. The rotary switch claimed in claim 1 wherein the movable contactassembly has positioning tabs and the drive member has cut out sectionsfor receiving said tabs.

5. The rotary switch claimed in claim 1 in which there are two leafsprings located on opposite sides of the drive members, said springsbeing in the form of a lazy W, the central apexes of the springsengaging the flutings of the drive member.

6. The rotary switch claimed in claim 5 and comprising slots in the sidewall of the casing for seating said springs.

7. The rotary switch claimed in claim 1 wherein the fixed contacts eachcomprises a terminal post extending through the bottom of the base.

8. The rotary switch claimed in claim 1 wherein the fixed contacts eaohcomprise an inner disc-shaped retaining member abutting the bottom ofthe base.

9. The rotary switch claimed in claim 8 wherein the upper and lowersurfaces of the disc-shaped contacting elements of the fixed contactsare bevelled and the upper surface of the inner retaining member isbevelled in a manner complementary to the bevelling of the lower surfaceof the corresponding disc-shaped contacting element. I i

10. A rotary switch comprising a base, a primary fixed contact in saidbase, a plurality of secondary fixed contacts in said base, each of saidprimary and secondary fixed contacts being electrically and structurallyinde pendent and each having at least one side thereof bevelled, arotatable resilient contacting assembly in said base for electricallyconnecting, selectively, said primary fixed conta-cts to said secondaryfixed contacts, a handle rotatable with respect to said base, and drivemeans engaging said contacting assembly and said handle whereby,rotation of said handle causing rotation of said drive means and saidcontacting assembly to efiect pure sliding contact between saidcontacting assembly and said fixed contacts.

11. The switch claimed in claim 10 and comprising means in said base,engaging said drive means, for limiting the rotation of said handle.

12. The switch claimed in claim 10 wherein the drive means comprises atubular member having a fluted section on one end and wherein saidhandle has an internally fluted socket for engaging said fluted sectionof said drive means. a

13. The switch claimed in claim 12 and including spring means seated insaid base and engaging the fluted section of said drive means to insurestepwise movement of said drive means.

14. A rotary switch comprising .a base, a handle rotatable with respectto said base, a primary fixed contact in said base, a plurality ofsecondary fixed contacts in said base, each of said fixed contactshaving a disc-shaped contacting element including opposed first andsecond sides, a movable contact assembly rotatable in said base andcomprising a resilient arcuate bifurcate section engaging the first andsecond sides of the primary fixed contact and a resilient bifurcatefinger adapted to engage the first and second sides of the secondaryfixed contacts and means connecting said movable contact assembly withsaid handle whereby rotation of said handle causes rotation of themovable contact assembly.

15. The switch claimed in claim 14 wherein the movable contact assemblycomprises two laminations each comprising a center part, an arcuatesection extending on one side thereof and a finger extending on theopposite side thereof, the corners of said arcuate section and thecorners of the fingers being flared forming entrances for the fixedcontacts.

16. The switch claimed in claim 15 wherein the means connecting themovable contact assembly comprises a tubular drive member having cut outsections on one end thereof and wherein the mowable contact elementshave positioning tabs engaging said out out sections.

References Cited by the Examiner UNITED STATES PATENTS 2,693,573 11/1954Perkins 20011 X 2,694,756 11/1954 Warnke 200-166 X 2,726,876 9/1956Glogau et al 20011 3,135,840 6/1964 Ausfeld 200-11 X ROBERT K.SCHA'EFER, Primary Examiner. J. R. SCOTT, Assistant Examiner.

1. A ROTARY SWITCH COMPRISING: A CYLINDRICAL BASE HAVING A BOTTOM AND ASIDE WALL, SAID BOTTOM HAVING A CENTRAL HUB, A RING ABOUT SAID HUB, SAIDRING AND SAID HUB DEFINING AN ANNULAR CHANNEL AND A STRUT EXTENDINGACROSS SAID CHANNEL FROM SAID RING TO SAID HUB; A PRIMARY FIXED CONTACTIN SAID BASE AND A PLURALITY OF SECONDARY FIXED CONTACTS IN SAID BASE,EACH OF SAID FIXED CONTACTS HAVING A DISC SHAPED CONTACTING ELEMENT; AMOVABLE CONTACT ASSEMBLY COMPRISING A BIFURCATE ARCUATE SECTION FORENGAGING THE DISC SHAPED ELEMENT OF THE PRIMARY FIXED CONTACT AND ABIFURCATE FINGER FOR ENGAGING THE DISC-LIKE MEMBERS OF THE SECONDARYCONTACTS; A HOLLOW CYLINDRICAL DRIVE MEMBER HAVING A FLUTED SECTION ANDA POSITIONING SECTION, SAID POSITIONING SECTION FITTING IN THE ANNULARCHANNEL OF SAID BASE AND HAVING MEANS ENGAGING THE MOVABLE CONTACTASSEMBLY WHEREBY ROTATION OF SAID DRIVE MEMBER CAUSES ROTATION OF THECONTACT ASSEMBLY; A LEAF SPRING SEATED IN SAID BASE AND ENGAGING THEFLUTING OF THE DRIVE MEMBER TO PROVIDE INDEXING WHEN SAID DRIVE MEMBERIS ROTATED; A HANDLE HAVING A SOCKET ENGAGING THE FLUTED SECTION OF THEDRIVE MEMBER, WHEREBY TURNING SAID HANDLE TURNS SAID DRIVE MEMBER; AHELICAL SPRING IN SAID HOLLOW DRIVE MEMBER PRESSING UPON SAID MOVABLECONTACT ASSEMBLY; AND A BOLT PASSING THROUGH THE HUB OF SAID BASE ANDTHREADED IN SAID HANDLE TO HOLD SAID HANDLE TO SAID BASE AGAINST THEACTION OF SAID HELICAL SPRING.